public CallOperator(StandaloneMetric caller, MetricExpression callee)
: base(caller, callee)
{
if (caller == null || callee == null)
{
throw new ArgumentNullException();
}
_caller = caller;
_callee = callee;
}
private StandaloneMetric ParseMetric()
{
Token token;
// Get name
if (!Expect(TokenType.Identifier, out token))
{
return(null);
}
var name = token.Value;
var parameters = new string[0];
var nextToken = PeekNextToken();
if (nextToken != null && nextToken.Type == TokenType.LeftBracket)
{
GetNextToken();
parameters = ParseParameters();
if (parameters == null)
{
return(null);
}
if (!Expect(TokenType.RightBracket, out token))
{
return(null);
}
}
// check if name is valid metric
if (!MetricEvaluationContext.NameToMetricMap.ContainsKey(name))
{
LastErrorMessage = string.Format("Undefined metric name {0}", name);
return(null);
}
var metricType = MetricEvaluationContext.NameToMetricMap[name];
StandaloneMetric metric = null;
try
{
var constructors = metricType.FindMembers(
MemberTypes.Constructor,
BindingFlags.Public | BindingFlags.Instance,
null,
null);
foreach (var constructor in constructors)
{
var parameterTypes = ((ConstructorInfo)constructor).GetParameters().Select(pi => pi.ParameterType).ToArray();
if (parameterTypes.Length != parameters.Length)
{
continue;
}
// try to convert parameters to the expected type
var objects = new object[parameterTypes.Length];
try
{
for (var i = 0; i < parameterTypes.Length; ++i)
{
objects[i] = Convert.ChangeType(parameters[i], parameterTypes[i]);
}
}
catch
{
continue;
}
// now try to create instance with converted parameters
metric = new StandaloneMetric((SerialMetric)Activator.CreateInstance(metricType, objects));
break;
}
if (metric == null)
{
LastErrorMessage = string.Format(
"Can't find proper constructor for metric {0} that can be initialized by parameters {1}",
metricType.Name,
string.Join(",", parameters));
return(null);
}
}
catch (Exception ex)
{
LastErrorMessage = string.Format(
"Create metric object {0} with parameter {1} failed. Exception {2}",
metricType.Name,
string.Join(",", parameters),
ex.ToString());
return(null);
}
return(metric);
}
private MetricExpression Parse()
{
// parse the first part, such as MA[20]
StandaloneMetric metric = ParseMetric();
if (metric == null)
{
return(null);
}
// parse the call operation part, such as (MA[20])
MetricExpression callee = null;
Token token = PeekNextToken();
if (token != null && token.Type == TokenType.LeftParenthese)
{
GetNextToken();
callee = Parse();
if (callee == null || !Expect(TokenType.RightParenthese, out token))
{
return(null);
}
}
// parse the selection part, such as .DIF
int fieldIndex = -1;
token = PeekNextToken();
if (token != null && token.Type == TokenType.Dot)
{
GetNextToken();
if (!Expect(TokenType.Identifier, out token))
{
return(null);
}
string field = token.Value;
// verify if the selection name is part of metric definition
Type metricType = metric.Metric.GetType();
MetricAttribute attribute = metricType.GetCustomAttribute <MetricAttribute>();
if (!attribute.NameToFieldIndexMap.ContainsKey(field))
{
LastErrorMessage = string.Format("{0} is not a valid subfield of metric {1}", field, metricType.Name);
return(null);
}
fieldIndex = attribute.NameToFieldIndexMap[field];
}
MetricExpression retValue = metric;
if (callee != null)
{
retValue = new CallOperator(metric, callee);
}
if (fieldIndex >= 0)
{
retValue = new SelectionOperator(retValue, fieldIndex);
}
return(retValue);
}
